The invention relates to a device and a method for determining the position of one or several communications satellites.
Determining the attitude and control, i.e. the angular attitude, when operating present-day satellites, requires a precision in the magnitude of 1/100xc2x0 for all three rotation axes. To meet these requirements, either star sensors or earth sensors which allow independent on-board operation, are available. Both measuring methods for determining the attitude of satellites are associated with the disadvantage that they require very considerable functional expenditure, in particular in relation to error detection. Star sensors which allow independent on-board operation are associated with the additional disadvantage in that in the region of the orbit of satellites there is intensive radiation with heavy atomic nuclei. Such radiation can only be reduced with great technical expenditure by respective hardening of the highly-integrated electronic components. However, there still remains a residual irradiation which acts on the electronic components, said radiation having a negative effect on the service life of said electronic components.
It is thus the object of the invention to provide a device and a method for determining the attitude of communications satellites which device and method meet the requirements for operational accuracy of attitude determination, and which can be realised with a minimum of technical expenditure, in particular by obviating the need for at least one precise sensor.
This object is met by the characteristics of the independent claims. Alternative embodiments are provided in the subordinate claims.
By using optical data transmission systems for determining the attitude of the satellites, said optical data transmission being necessary anyway for the operation of communications satellites, the device and the method of the invention require relatively little technical expenditure because the data required is already available on board the satellite and can be processed using relatively simple methods.